What’s The Deal With TCO2, Anyway?

by | 04.18.2017 | 4:00pm

An announcement from the Arkansas State Racing Commission in early March that it would begin randomly testing Oaklawn Park runners for elevated TCO2 was widely lauded as another step toward improved integrity in the state. The commission adopted a TCO2 threshold in February which brought its rules for allowable levels in line with national standards. Along with out-of-competition testing and broader post-race drug tests, this was the latest in a series of moves designed to improve welfare and safety in Arkansas racing.

The decision did make us wonder – wasn't TCO2 something the industry dealt with a long time ago? Kentucky and Louisiana became the last states to outlaw manipulation of TCO2 levels in the 1990s and California started testing for elevated levels in 2004. Although regulators say TCO2 overages aren't ubiquitous, regulations (and drug testing contracts) regarding its detection vary between states.

What is TCO2, again?

It's important to understand TCO2, or total carbon dioxide, is present in horses naturally as a result of normal metabolic processes. TCO2 varies in a horse's blood as it increases or decreases in balance with electrolytes like sodium, potassium, and chloride, as well as protein and lactate. Sodium and potassium sit on one side of the equation, with TCO2, protein, lactate, and chloride on the other; if something makes one part of the equation go up, an element on the other side of the equation must go down to balance it out.

TCO2 may increase or decrease in response to electrolyte or protein changes from certain feeds, as well as exercise (which increases lactate as the muscles are used, thereby reducing TCO2). When someone tries to manipulate TCO2, they're hoping to increase TCO2 levels and decrease lactate levels. Lactate is the byproduct of aerobic exercise and causes muscles to feel tired.

A study published in the Equine Veterinary Journal in 2006 showed a number of other factors associated with TCO2 levels, including gender (male horses tended to have higher TCO2 levels), class of race (maidens tended to have lower TCO2), finish position (horses hitting the board had higher TCO2 than those that did not), and oddly, cloudy weather. It's unclear what caused these differences, and whether TCO2 levels explained a horse's performance (with a better performance being a result of higher TCO2) or if TCO2 readings were more a marker of a given horse's fitness.

The study also found trainer- and horse-specific trends, which doesn't necessarily suggest trainers in the study were intentionally manipulating TCO2 levels. It's possible different barns might create different environments for TCO2 readings given their combination of feed and exercise programs.

One thing that probably doesn't impact TCO2: electrolyte pastes and supplements. Commercially-available electrolyte supplements contain all three minerals (sodium, potassium, and chloride) involved in the TCO2 equation, thereby preventing an imbalance.

Milkshaking, one method of trying to artificially manipulate TCO2, involves delivering a dose of sodium ions along with bicarbonate, commonly from an ingredient like baking soda. This is intended to elevate TCO2 and therefore reduce lactate as the horse's body works to keep everything in balance. Milkshaking is thought to have crossed into Thoroughbred racing from the Standardbred world in the late 1980s. The practice gets its name from the slurry consistency of the paste delivered directly to the horse's stomach via a nasogastric tube. Some trainers evolved the practice to include “bullets” of a similar paste-like mix, given with a dosing gun to the back of the throat.

The problem with both these delivery methods, said HFL Sport Science Laboratory Director Dr. Richard Sams, is they may not get enough baking soda in most horses to have an impact. Baking soda doesn't dissolve easily, which is why the slurry is so thick, so only a portion of it could be absorbed to adjust the bicarbonate level in the blood. That's if the trainer inserts the nasogastric tube correctly and doesn't accidentally pump the slurry into the horse's lungs instead (which Sams said has happened). Even once it gets there, Sams isn't sure a milkshake necessarily has the impact trainers might hope.

“Because the bicarbonate [in the horse's blood] is a physiological response to different factors, I don't see how it can directly influence other factors,” said Sams. “For example, it is not going to be able to suppress the formation of lactate ion from lactic acid. The lactic acid is a byproduct of anaerobic metabolism of glucose. That's what happens during the race.”

lab test tubeRacing Medication and Testing Consortium Executive Director and COO Dr. Dionne Benson has quizzed trainers and regulators who were around in the days of frequent milkshaking and learned the practice seemed to be hit and miss, depending upon the individual.

“From what I understand from talking to people, just like everything, it doesn't work on every horse,” said Benson. “There are some horses who had great benefit and some horses who didn't improve at all. Without knowing what people did, I'm guessing what happened is they tried different things on different horses and see what improved that individual. And I'm sure you had people who did it to every horse, because if it worked on one, it might work on all of them.”

Furosemide (Lasix) also impacts TCO2, since it dehydrates horses and reduces chloride, which prompts an increase of TCO2 to compensate. For this reason, horses running with furosemide are expected to have slightly elevated TCO2 compared to those not receiving the drug. If a horse's TCO2 is elevated, Sams said he can tell whether furosemide is to blame based on the chloride levels. Unusual electrolyte levels along with high TCO2 could also indicate a horse is ill or suffering from a chronic condition.

The testing process for TCO2 requires fairly rapid action, as it can only be measured accurately in blood for a limited time after collection. Proper storage of the blood sample is also important because electrolytes inside red blood cells can shift if the sample is not spun properly (a fact which was the basis for trainer Karl Broberg's fight against two TCO2 overages in 2013), creating an erroneous reading.

State by state

Unsurprisingly, thresholds for TCO2 vary across states. The international standard is 36 millimoles per liter, while the recommended United States threshold is 37 mmol/L. That figure was already supposed to take into account the needed flexibility for horses running on furosemide, but a few states – Arkansas, West Virginia, and New York – have rules allowing an extra two mmol/L for horses running with furosemide.

According to the website Horse Racing Reform, eight states including Florida, Maryland, and Oklahoma, do not have published rules quantifying the threshold for TCO2. As with post-race drug testing, there may also be a discrepancy between published rules and testing procedures. Florida's current drug testing contract does not address TCO2 specifically. Louisiana's contract specifies only that blood samples “may also be used to investigate the presence of alkalinizing agents,” which leaves the door open for the lab to start or stop testing for it at any time.

In states where testing is taking place, TCO2 samples are obtained similarly to cobalt or out-of-competition samples in that tests are conducted on a relatively small portion of the population at random. At Kentucky racetracks, one or two races are chosen randomly and the entire field is tested to prevent any perceived disadvantage to individual runners from being pulled aside and upset prior to the race. Similar policies are in place in other states requiring random testing of all horses in one or two races per day.

International testing for TCO2 varies widely. Ireland only recently began testing for the substance. Testing is not performed at all in Japan, where horses are under surveillance sufficiently officials feel they are not likely to be milkshaked. Random sampling takes place in several international jurisdictions, and in Singapore, every horse is sampled before every race (though no TCO2 overages have been found in 11 years).

The penalties for a TCO2 positive in the United States can be stiff if the trainer and owner involved are repeat offenders of medication rules. In Kentucky, if a horse tests positive for elevated TCO2 and the trainer already has one other positive drug test in the past 365 days, suspensions can run 90 to 180 days. A total of four or more total testing offenses in a year, and the trainer may get a year suspension or a ban. California has a similar program graduating penalties as a trainer is found guilty of multiple TCO2 violations.

Association of Racing Commissioners International model rules support a Class B penalty for TCO2 excesses, which results in disqualification and purse loss for owners and a minimum 15-day suspension and $500 fine for trainers on their first offense.

A handful of states have adopted the entire drug overage penalty schedule laid out by the ARCI, though states not adopting the schedule may have similar rules specific to TCO2.

“We don't have very many of these [in Kentucky],” said Sams. “I think the trainers have made the decision it just isn't worth it. The benefit doesn't outweigh the risk. I think maybe more importantly, I think trainers here realize that others aren't gaining an advantage by using bicarbonate. That's probably the greatest disincentive.”

  • Tinky


    The problem with both these delivery methods, said HFL Sport Science Laboratory Director Dr. Richard Sams, is they may not get enough baking soda in most horses to have an impact. Baking soda doesn’t dissolve easily, which is why the slurry is so thick, so only a portion of it could be absorbed to adjust the bicarbonate level in the blood. That’s if the trainer inserts the nasogastric tube correctly and doesn’t accidentally pump the slurry into the horse’s lungs instead (which Sams said has happened). Even once it gets there, Sams isn’t sure a milkshake necessarily has the impact trainers might hope.

    With all due respect to Dr. Sams, most miikshaking, at least during its looong heyday, was physically done by vets, not trainers. Secondly, as is the case with virtually all forms of PEDs, there wasn’t only one, simple recipe used, and some vets became highly proficient at administering them.

    I’m also getting tired of the ludicrous suggestion that milkshaking isn’t, or wasn’t effective, as it is pure poppycock. When properly administered, it was/is a potent PED. They have been used promiscuously, and successfully, by too many trainers to name, and over a very long period of time. And while it is certainly true that not all horses react(ed) the same to them, and that there are varying degrees of success, the cocktail has helped countless thousands of runners perform beyond their natural capabilities, and artificially enhanced the records of trainers including some that are in the HOF.

    • McGov

      100 % agree. The use of baking soda can benefit a horse and give them a HUGE advantage. Without question.

    • Michael Castellano

      I remember milk shaking allegations being made against some NY trainers as far back as the 70s, maybe even earlier than that. One trainer in particular apparently had great success with it, however he did it. I’m sure there were others.

    • I do know a few trainers that are better than most vet’s at tubing horses. and that’s going back a few years, I also know it’s sometimes given oraly using a syeringe with the end cut off (30cc or larger) mixed with water and other stuff by trainers.
      i use that method for giving SMZ’s (antibiotic)
      not to argue but just saying

      • Tinky

        Excellent point. I was simply trying to point out that whether vet or trainer, there was more than enough knowledge available to allow effective applications in most cases.

        • It had high popularity in QH racing, that breed has a higher tendency to tie up in the hind. Never did observe that it actually helped with lactose buildup. There was a study done via muscle biopsy that indicated it was not affective for that intended purpose.
          But did have other affects of enhancement princably having to due with potassium/calcium channel affects on Hart rate. Some believe that was part of the sudden death issues seen during it high use. Could be wrong but I believe that was published in the “Adams”series of veternary curculium

    • cathyj

      Baking soda usually administered by trainers in the harness industry. Maybe Dr. Sams was including this demographic.

    • kmlman

      I agree 100% Tinky. I read this article and could not really understand why Dr. Sams’ main theme seemed to be his claim that the efficacy of milk shaking was in question. That was a debate that was resolved long ago–as anyone based in Cali is acutely aware–so why are we having the debate again now? The issue is whether states have the money and the willingness to test for it.

  • Gate To Wire

    Florida doesn’t actually test for TC02. They stopped a few years ago because of budget.
    That is why so many horses get magically slower when they leave in the spring to race in KY and NY

    • Watcher

      It’s a head-scratcher that testing would be stopped over budget concerns. The CO2 test is dirt cheap and one of the most basic tests in the lab industry.
      Just to clarify, the test may be called CO2 but it is a composite of bicarbonate and carbon dioxide in a ratio of ~ 20:1.

      • Greg

        The cost is in the collection and testing by in individual.

  • McGov

    I think there is much more to tubing horses than simply baking soda. The people that do these kinds of things to a horse are a desperate variety and typically include much more…..or so I’ve heard.
    Thank you for another well written and very informative article.

    • Greg

      Just baking soda and water will do the trick, if it’s going to help.

  • Hamish

    Look no further than the Uvari indictments in NY, early 2000’s, where a horse named A One Rocket was milkshaked and heavily bet. This tactic is old, but according to law enforcement, quite effective while playing a hand in race outcome manipulation. Hard to believe this has changed much since then.

  • Bad Lucky

    Yogurt, say no more!

  • Fred and Joan Booth

    We wonder how cloudy weather affects these TCO2 levels? Many races here in the NW are run under cool cloudy conditions. Like in most of the time especially in the winter or early spring. The shakes shown look yummy! We bet some of our horses would like them to eat.

  • FastBernieB

    Brings back memories of the Ontario Standardbred tracks in the 80s. Post race comments by track regulars following decisive wins usually included Dairy Queen references. Previously unknown trainers rose to prominence during this era. There were a few suspicious deaths of cheaper horses where the rumor was that the tube was inserted into the wrong opening by inept trainers desperate for an edge. When testing caught up to the “milkshakers” many faded back into mediocrity while others who continued to have success were rumored to be a little more prolific with their chemistry sets. If there is one constant over the years it’s that racetrackers are always suspicious of the newly successful – sadly, it is often with good reason.

  • As a trainer who actually milk-shaked back in the early 1990s, I agree completely with Dr. Sams. Some of the time, horses seemed to race well on it, but a lot of times, ho-hum! One key was never to over-use it, no more than once every 4 starts or so. Get greedy and tube em every time, and they quickly lost their form. I love it how all these “experts” on this place who never cleaned out a stall or a sheath or trained a horse thinks a milk-shake is so bloody potent in creating a winner. I guarantee you that for every doped horse, far more raced badly than well on the stuff. Far more inside money has been lost on doped horses than profited on them. Pre-racing is the darling of the disgruntled bettor and naive owner to blame chemicals. So goes the mystique of doping and race horses. If only making winners were really that easy.

    • Condor

      Great post. Anymore tales of yester-year tricks and old fashioned rogues tales?

  • greg

    Essentially they’re saying we started testing for this long ago, however since our testing wasn’t effective in stopping it we’re going to begin testing for it again. What’s the quote, You’re crazy if you do the same thing over and over and expect a different result

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